Vial of Felix Felicis
Brilliant Gryffindor Boy's Bedroom
Harry Potter's Pocket
Felix Felicis, known colloquially as Liquid Luck, is a potion that, as the name suggests, grants the drinker immense luck. As such, its use is banned in Quidditch and all other organised competitions. Difficult to brew and dangerous in large doses, Harry Potter was gifted a vial of Liquid Luck after brewing the best Draught of Living Death in Potions. He pretended to use it to boost Ron Weasley's confidence in the Gryffindor Quidditch tryouts. He then went on to use it in earnest to get a memory of Tom Riddle from Professor Slughorn. The rest he gifted to his close friends during the Battle of Hogwarts.